Suggested enhancements to e-survey published

The top 30 suggested enhancements to Landonline e-survey have now been published on the Landonline website.

These enhancements have been prioritised through the existing process, which was outlined in the November/December 2007 edition of Landwrap.

When considering enhancements for Landonline releases, the candidates are analysed to assess the complexity of implementation. Enhancements will be implemented where possible, however, the final choice of what is included in any release is a balance of the effort, time, cost and urgency required relative to the current programme of work.

Listed alphabetically rather than in order of priority, the enhancement with the highest score may not necessarily be implemented first.

Next steps

A business case will now be developed to implement the recommendations in the final report Phase 2 – Landonline Enhancement Prioritisation Process Proof of Concept published last month.

For more information, refer to the new e-survey enhancements section on this website.

Assisting surveyors in non-SDC areas – update

Since June 2008, LINZ has been working with the survey industry on a programme of work looking at how to assist surveyors working in non Survey-Accurate Digital Cadastre (SDC) areas.

Work completed so far includes:

• an enhancement in Release 3.1 that allows the exception process to be accessed at any stage of the survey
• clearing the backlog of cadastral network adjustments
• submitting two datasets, and
• a project to improve spatial accuracy.

Refer to the August 2008 edition of Landwrap for further information.

Improving spatial accuracy

One of the key activities has been conducting a data readjustment pilot to improve the spatial accuracy of data outside SDC areas. The pilot began in June 2008 and was anticipated to take three months, but due to technical issues it has taken longer to complete.

Data outside SDC areas was transferred into Landonline from the Digital Cadastral Database (DCDB). In most cases, it was digitised into the DCDB from Cadastral Record Maps. Thus, the data accuracy is limited by the scale at which the data was digitised.

Surveyors and other professionals who work regularly with this data will be aware that in some areas it can be tens of metres out of position. This can make the e-survey process more time-consuming and makes it difficult to combine the cadastral data with other datasets (such as accurate aerial photography).

Data re-adjustment pilot

In many cases the parcel shapes are reasonably accurate, but the location is incorrect. Therefore, a methodology that enables data to be shifted as a block is being trialled.

The basic process is to combine the digitised data with data from e-surveys in Landonline. All the data is then adjusted in terms of geodetic control.

The pilot has worked through a number of technical issues that arise when running adjustments with low-accuracy digitised data. For example, combining low and high accuracy data can lead to distortions arising in the parcel fabric where part of a parcel has accurate data from an adjoining e-survey and the rest of the parcel does not.

Results achieved to date are promising, with significant improvements being made to the quality of the spatial data in non-SDC areas. An example is shown in the figure below:

Next steps

For the next three months, work on refining the process will continue. In particular, there will be a focus on how best to deal with natural boundaries that are affected by large movements.

Accurate estimates of the time and resources required to carry out these adjustments will also be obtained.

LINZ 2009/10 geodetic survey programme

LINZ carries out annual geodetic control surveys to upgrade existing marks and extend control into developing areas. We also maintain survey mark beacons and other mark protection structures on an ongoing basis.

Feedback from the survey profession, other interest groups and members of the public helps us decide which marks and areas to survey and maintain.

2009/10 geodetic survey programme

LINZ is putting together the 2009/10 geodetic survey programme, which will begin in August 2009.

The programme for this year will be nationwide, focusing on both the continued upgrading of important geodetic marks that have not yet been surveyed and adjusted in terms of NZGD2000 (ie less than 5th order NZGD2000 marks), as well as increasing the density of survey control marks in rapidly developing areas where survey activity is concentrated.

Last year, with input from geodetic network users, we were able to:

• upgrade approximately 800 marks to 5th Order standard, and
• maintain beacons and protection structures on approximately 250 existing control marks across the country.

In addition to this work, the programme has enabled the:

• ongoing data capture and re-adjustment of NZGD1949 control to 5th Order standard, and
• continuing development, upgrade and maintenance of the PositioNZ network to facilitate the use of GPS technologies in the control network.

Request for input

LINZ relies on the knowledge of surveyors and others working in local areas to meet the requirements for geodetic control. We would appreciate any information you have about:

• developing areas that require increased geodetic control
• areas where there are gaps and inconsistencies within the existing control, and
• existing high order geodetic marks that require physical maintenance.

You can view the schedules of marks and areas included in the 2008/09 programme on the LINZ website.

Please forward any recommendations for marks to be upgraded or maintained, and priority areas for new marks, by 29 May 2009, by:

• emailing info@linz.govt.nz with 'Geodetic Programme recommendations' in the subject line
• posting to Customer Services Geodetic, Land Information New Zealand, Private Box 5501, Wellington 6145, or
• faxing to 04 498 3837.